Health Impact Assessment HIA is a tool that allows health issues to be taken into account when key decisions are being made about development. It is a relatively new methodology for evaluating the potential or actual impact of a policy on a defined population. This may be a decision regarding projects, plans, programmes, activities or individual draft measures. The implementation of the programmes and policies produces an impact on peolpe's health and therefore the quality of their life. It is important to apply HIA to the decisions of the local authority anticipating and correcting the negative effects and maximising the positive ones.

An Environmental Impact Assessment EIA shall when this is relevant include a HIA. The predominant way of comparing the health effects of the project is to relate these to the current and future standard, guidance and limit values. Standards etc are used instead of describing the impact, the implication being that if such values are not exceeded, changes in the environment have no effects on human health. This approach is unscientific and does not accord with present knowledge concerning for instance the effects of exhaust gases.Standards have limited ability to describe the health impacts for the population concerned since they are an expression of the level at which it was considered that the limit was unacceptable disturbance and effects on people could be set when the standard value was ratified. Standards, threshold limit values and similar are also altered in stages, subject to considerable delay in relation to the constant increase in knowledge.

One of the benefits of the HIA to developers is that it is able to demonstrate positive effects for the community, as well as negative impacts. EIA tends to highlight the negative aspects. Thus, the major incentive for developers is the possibility that HIA can be used to promote the proposal.

In applications for EU structural funds, for example, ecological, social and economic assessments are to be weighed against each other, since the aim is to even out social and economic inequalities within the Union.A broad range of skills is needed to be able to access how a decision affects the health of different population groups. It is very important that Studio Messori has a multi-skilled group with expertise in different fields such as social services, the environment, planning and public health science.

Over the past five years there has been growing use of HIA and organisations including the World Health Organisation, the EU, the regional government of Emilia-Romagna have been promoting their use. Studio Messori has already undertaken several HIA, largely for assessment of new policies by the public sector.